JPH0121882B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shape detection device that detects deformation of the front and rear ends of a steel material that occurs during rolling, for example, in a hot rolling process of steel.

The deformation of the tip of the steel material that occurs during hot rolling of steel is
Unequal loads were applied to the rolling rolls in subsequent stages, causing damage to the rolls and producing defective materials.

In order to prevent this, conventionally, an operator visually observes the material and operates a cutting machine to cut the material at an appropriate location.
Therefore, the deformation of the tip of the steel material is automatically detected, the deformed part is cut to the minimum necessary extent, and the material is fed to the next stage of rolls, eliminating the effects of uneven load and preventing damage to the rolls. In anticipation of this, the following shape detection devices have been proposed.

FIG. 1 shows a block diagram of a conventional device. The width of a red-hot steel plate 1 flowing through a hot rolling process is measured by an optical system using a lens 2 and a plurality of photoelectric elements 3 arranged in a line to measure the presence or absence of a steel plate on a measurement line 3a. The photoelectric elements 3 generate an output proportional to the temperature of the steel plate, this output is amplified by an amplifier 4, and an analog to digital conversion circuit (A/D) 5 converts the output signal of each photoelectric element 3 into a digital quantity. Convert to
Already, the signal of the portion of the photoelectric element 3 where the image of the steel plate 1 is formed has a logical value of "1", and the signal of the portion of the photoelectric element 3 where the image of the steel plate 1 does not exist has a logical value of "0". When the output of the A/D 5 is counted by a width measurement circuit 6 comprising a counter circuit, a measurement value corresponding to the width of the steel plate 1 is obtained.

The comparison circuit 8 compares the width measurement value of the steel plate 1 with the width reference value W given from the input terminal 7, and when the width of the steel plate 1 falls within a certain tolerance value smaller than W, the comparison circuit 8 outputs a signal. A cutting signal is given to the cutting machine control device 9, and the tip of the steel plate 1 is cut.

That is, as shown in Fig. 2, if the width of the central portion of the steel plate 1 is W, then the width KW indicated by the dotted line at the tip of the steel plate 1 is
Cutting can be performed by detecting the position of the board width (k<1).

Conventional equipment is configured as described above, so it can be used to detect cases where areas other than the steel plate image become bright due to light scattered by the background or fine particles in the air, especially when the temperature change of the steel plate itself is large under the above conditions. However, the digitization process, which only extracts the image of the steel plate, had the drawback of causing errors.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above.The analog steel plate signal is quantized into multi-values and stored in memory, and this steel plate signal is sent to multiple locations corresponding to the positions on the steel plate. The object of the present invention is to provide a shape detection device that is not affected by scattered signals or temperature distribution of the steel plate by dividing the shape, creating a temperature histogram for each part, finding an optimal threshold value, and binarizing it.

An embodiment of the present invention will be described below with reference to FIG. The components from the red-hot steel plate 1 to the cutting machine control device 9 correspond to those described in connection with the conventional shape detection device. Reference numeral 10 denotes a quantization circuit that quantizes a steel plate image signal obtained in an analog manner using multiple values, 11 a memory that stores the quantized steel plate image signal, and 12 a (local ) read out, create a histogram, and find the optimal threshold 2
The local binarization circuit 13 is a scanning circuit that receives a drive signal P generated every time the steel plate 1 advances a certain distance in the detection area, scans the photoelectric element group 8a, and sends out an output. The device configured in this way has N
The output of the photoelectric element group 3 (hereinafter referred to as a video signal) consisting of photoelectric elements is scanned by a scanning circuit 14 once every time the steel plate advances a certain distance in the direction of the arrow. and read out. This video signal is converted into a digital signal having multiple quantization levels by the quantization circuit 10 via the amplifier 4, and is stored in the memory 11 according to the above-mentioned scanning order. This operation is performed a number of scanning times M determined from the detection field of view and scanning interval set in advance, and as a result, a video image as shown in FIG. 4a is obtained in the memory 11, for example. However, as shown by the diagonal line A in the same figure, scattered signals, which are disturbance components, as described in the section on the drawbacks of the conventional device, are present. Since this scattered signal is generated by radiated light from the steel plate 1, the scattered light from the high temperature portions of the steel plate 1, that is, the portions E and F shown in FIG. 4C has a high signal level _V1 . On the other hand, the steel plate 1 has low temperature parts as shown in c and d in Figure 4c, and if the signal level V ₂ of this part becomes lower than the signal level V ₁ mentioned above, the fixed If the binarization is performed using a threshold value of , an error will occur as shown by the solid line in FIG. 4b. 2
In order to remove the above-mentioned error, the value converting circuit 12 performs the following steps.
First, the central part of the steel plate 1 where the temperature is high, that is, the fifth
A histogram is created by reading out the video signal in the area shown in the figure from the memory 11. As an example of this histogram is shown in Fig. 6, the horizontal axis shows the level V of the video signal, and the vertical axis shows the frequency N. In the above-mentioned section G of the steel plate 1, since only the relatively high temperature section, the steel plate The scattering area and the scattering area can be clearly distinguished on the histogram signal as shown in FIGS. Therefore, by using the video signal level V _s indicating the boundary between the two as a threshold value, the above-mentioned portion (g) can be binarized with high precision, and the result is stored in the memory 11 again. Next, the points ``chi'' and ``li'', which are the ends of the video image, are determined by the above binarization process, so the points ``nu'' and ``ru'' that divide the steel plate 1 in the width direction of the video image at a ratio of 1:2:1, for example, are determined. Then, the histogram processing is performed on the central region in the width direction, which is relatively high temperature as described above, and the binarization processing is performed using the threshold value, and the results are stored in the memory 11 again.

Next, from the above processing, other points of the video image,
Since the force is calculated from the preset amount L, a histogram is created in the same manner as above for the low temperature area R, which is the corner part of the steel plate 1, from the points Yo and Ta calculated from the preset amount L, and the binarization process is performed. It is stored in the memory 11. In this case as well, the steel plate portion and the scattering portion can be clearly distinguished on the histogram signal since they are only relatively low-temperature portions. Subsequently, the remaining areas (X and X) are similarly binarized and stored in the memory 11. If the video image is divided and binarized in this way, it will be divided into sections corresponding to the characteristics of the temperature distribution of the steel plate 1, and the scattering part and the steel plate part can be clearly separated on the histogram signal, making it possible to perform error-free binarization processing. is realized, and the video image after the binarization process is stored in the memory 11. The operation of generating a disconnection signal from this result is similar to that of the conventional device and has already been described.

Note that the above embodiment shows the minimum number of divisions necessary for a binarization circuit, and it may be divided into smaller numbers based on a signal-like concept.

Further, in the above embodiment, the local binarization circuit has been described as hardware, but it may be executed in software by a computer capable of processing the same function.
Furthermore, as an imaging means for steel plate signals, a function of adjusting the amount of received light using various filters, an automatic diaphragm mechanism, etc. may be added.

As described above, according to the present invention, the processing area is divided based on the characteristics of the temperature distribution of the steel plate, and the threshold value is determined by histogram processing for each portion.
Since it is converted into a value, a shape detection device that is not affected by scattered light can be obtained, which has a great practical effect.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a conventional device.
Fig. 2 is a diagram showing the shape of the tip of the steel plate to explain its operation, Fig. 3 is a block diagram showing the configuration of an embodiment of the present invention, and Figs. 4 to 6 each explain its operation. This is a diagram for In the figure, 1 is a steel plate, 2 is a lens, 3 is a photoelectric element group, 4 is an amplifier, 10 is a quantization circuit, 11 is a memory, 12 is a binarization circuit, and 13 is a scanning circuit. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A detection means for forming a steel plate image on a plurality of photoelectric element groups and generating a scanning electric signal corresponding to the temperature of the steel plate, and a scanning interval of the detection means for forming a steel plate image on a plurality of photoelectric element groups. a scanning means for controlling according to the traveling distance; a memory means for storing a multi-valued signal obtained by a quantization means for multi-valued the detection signal obtained by the detection means; means for dividing the quantized signal into a plurality of regions corresponding to the temperature distribution of the steel plate, determining a threshold level for each region, and binarizing each of the divided quantized signals; and the binarized signal. A shape detecting device comprising: a width measuring means for determining the width of each scanning portion of the steel plate; and a comparing means for comparing this width signal with a prescribed width value set in advance and outputting the result. 2. The quantized signal is divided into a region where the high temperature part of the steel plate is divided in the width direction, a region in the center of the three parts divided in a predetermined ratio in the width direction, and a part of the steel plate on both sides of the third part. 2. The shape detecting device according to claim 1, wherein the shape detecting device is divided into a region (R) including a predetermined portion of the tip of the shape and two remaining regions (S) and (T).